From: Andrey Konovalov andreyknvl@google.com
[ Upstream commit 51dedad06b5f6c3eea7ec1069631b1ef7796912a ]
Similarly to "kasan, slub: move kasan_poison_slab hook before page_address", move kasan_poison_slab() before alloc_slabmgmt(), which calls page_address(), to make page_address() return value to be non-tagged. This, combined with calling kasan_reset_tag() for off-slab slab management object, leads to freelist being stored non-tagged.
Link: http://lkml.kernel.org/r/dfb53b44a4d00de3879a05a9f04c1f55e584f7a1.1550602886... Signed-off-by: Andrey Konovalov andreyknvl@google.com Tested-by: Qian Cai cai@lca.pw Cc: Alexander Potapenko glider@google.com Cc: Andrey Ryabinin aryabinin@virtuozzo.com Cc: Catalin Marinas catalin.marinas@arm.com Cc: Dmitry Vyukov dvyukov@google.com Cc: Evgeniy Stepanov eugenis@google.com Cc: Kostya Serebryany kcc@google.com Cc: Vincenzo Frascino vincenzo.frascino@arm.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- mm/slab.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/mm/slab.c b/mm/slab.c index 813bd89c263b..52c0420e4f93 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -2381,6 +2381,7 @@ static void *alloc_slabmgmt(struct kmem_cache *cachep, /* Slab management obj is off-slab. */ freelist = kmem_cache_alloc_node(cachep->freelist_cache, local_flags, nodeid); + freelist = kasan_reset_tag(freelist); if (!freelist) return NULL; } else { @@ -2694,6 +2695,13 @@ static struct page *cache_grow_begin(struct kmem_cache *cachep,
offset *= cachep->colour_off;
+ /* + * Call kasan_poison_slab() before calling alloc_slabmgmt(), so + * page_address() in the latter returns a non-tagged pointer, + * as it should be for slab pages. + */ + kasan_poison_slab(page); + /* Get slab management. */ freelist = alloc_slabmgmt(cachep, page, offset, local_flags & ~GFP_CONSTRAINT_MASK, page_node); @@ -2702,7 +2710,6 @@ static struct page *cache_grow_begin(struct kmem_cache *cachep,
slab_map_pages(cachep, page, freelist);
- kasan_poison_slab(page); cache_init_objs(cachep, page);
if (gfpflags_allow_blocking(local_flags))